Beeline flow finishing method and apparatus



June 17, 1969 HISAMINE KOBAYASHI 3,449,371

BEELINE FLOW FINISHING METHOD AND APPARATUS Filed March 21, 1967 Sheetof s J1me 1969 HISAMINE KOBAYASHI 3, 9,

BEELINE FLOW FINISHING METHOD AND APPARATUS Filed March 21, 1967 Sheet 2of 5 FIG. 5

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June 17, 1969 HISAMINE KOBAYASHI 3,449,871

BEELINE FLOW FINISHING METHOD AND APPARATUS Filed March 21, 196'? FIG. 9

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United States Patent O US. Cl. 51-317 2 Claims ABSTRACT OF THEDISCLOSURE A carrier device of U-shaped endless belt type composed of adurable wire net is tightly spanned between a pair of vertical beltwheels and its bottom is supported by a plurality of bearing rollerswhile each of its side walls is supported by a plurality of guiderollers except for the ranges of the belt wheels. A quantity ofabrasives is loaded in the form of a loose layer into the device. One ofthe belt wheels is driven to rotate the device and therefore theabrasive layer is moved in one direction in the horizontal plane.Workpieces are moved one after another in counterfiow relation in eitheror both of the rectilinear portions of the traveling abrasive layer, Ifdesired, the workpieces may push against the surface of the rectilinearabrasive portion. Also a layer of abrasives can be rotated in a verticalplane. A carrier device of channeled endless belt type composed of aflexible material is tightly spanned between a pair of horizontal beltwheels such that the major part of its upper rectilinear section formedbetween the belt wheels is of a substantially U-shaped cross sectionconfined by a plurality of roller sets such as above described forpurpose of surface finishing while the remaining section of the deviceshas a closed cross sectional profile by having a plural sets of fourrollers disposed on four sides of the device excepting that the insiderollers are omitted in the range of each belt wheel. Further a pair ofchannelled endless belts can be juxtaposed into an X-shaped arrangementin the respective vertical planes and be rotated in the oppositedirections. A layer of abrasives is formed in the ascending upperrectilinear section of each traveling belt and is transferred from itstop end onto the other ascending rectilinear belt section through atransfer chute. Workpieces are successively passed through one of therectilinear stream of the abrasive layer from its upper end to its lowerend and then transferred to the other rectilinear stream with theirorientation remaining unchanged followed by the similar passage throughthe other stream. Alternatively both rectilinear streams may be utilizedfor separate finishing operations. Preferably the speed of theworkpieces relative to the rectilinear abrasive stream ranges from 70 to500 meters per minute and the finishing time ranges from seconds tominutes. The rectilinear abrasive stream has a length of from less than1 to more than 10 meters. The abrasives may be of either dry or wettype.

mass within a finishing barrel which conditions depend upon theconfiguraton of the barrel and the type of drive therefor involved. Bythe term mass is meant a mixture of workpieces to be finished, abrasivesand other materials charged in a finishing barrel. Those limitationslead to other limitations as to the configuration and size of theworkpieces and to their amount charged in each barrel also determined bythe configuration of the barrel and the type of drive therefor.Accordingly, the conventional methods have successfuly surface finishedworkpieces relatively small in size and symmetrical in configuration butthey could scarcely succeed with both large-sized long Workpieces andthe special portions of small-sized workpieces. For example, suchmethods could not surface finish mufllers for use in autobicycles,bumpers, radiator grilles and decorative straps for use in automobilesetc.

It is, accordingly, an object of the invention to provide a new andimproved method of continuously and automatically effecting surfacefinishing of workpieces regardless of their size and configuration andespecially of largesized, long workpieces.

It is another object of the invention to provide a new and improvedmethod of automatically effecting surface finishing of workpieces on thebasis of production line.

Briefly, the invention accomplishes the above cited objects by theprovision of a method of surface finishing workpieces, comprising thesteps of establishing a stream of loose abrasives circulating at leastpartly along a rectilinear path while that portion of the abrasivestream moving along the rectilinear path has a substantially uniformdensity and a predetermined cross sectional profile, and moving theworkpieces, one after another, relative to the rectilinear portion ofthe abrasives stream at a predetermined relative speed in a directionopposite to the direction of the stream while maintaining the workpiecesin surface-finishing engagement with the rectilinear stream portion.

The speed of the workpieces relative to the rectilinear stream portionmay preferably range from to 500 meters per minute.

The invention also contemplates to provide a new and improved apparatusfor carrying out the surface finishing method as above outlined. Theapparatus comprises carrier means of channelled endless belt typecomposed of a flexible durable material, a pair of driving belt wheeland a turning belt wheel for spanning the carrier means in tensionedstate to form a pair of parallel rectilinear sections therebetween, aquantity of abrasives loosely and uniformly distributed in the form of alayer within the carrier means, means for maintaining a substantially U-shaped cross section of at least one of said rectilinear section of saidcarrier means, and means for holding and driving the workpieces oneafter another to move them at a predetermined relative speed in adirection opposite to a direction a rectilinear stream portion of theabrasive layer in the U-shaped rectilinear section of the carrier meansdriven by the driving belt wheel while maintaining the workpieces insurface-finishing engagement with the rectilinear stream portion.

In a preferred embodiment, the carrier device composed of a flexibledurable wire net may be spanned in tensioned state between a pair ofvertical belt wheels and has a bottom supported by a plurality ofbearing rollers and both side walls each supported by guide rollersexcept for the range of each belt wheel whereby the cross section of thedevice is maintained a substantially U-shaped. Thus the carrier deviceis rotatable in one direction in a horizontal plane to establish a pairof rectilinear stream portions of an abrasive layer loaded in the devicefor purpose of surface finishing.

In order to surface finish relatively small-sized workpieces, a carrierdevice of channelled endless belt type maybe rotated in tensioned statein a vertical plane between a pair of horizontal belt wheels. The majorpart of the upper rectilinear section of the carrier device may besupported a plural sets of rollers such as above described to have asubstantially U-shaped cross section. In order to prevent a layer ofabrasive formed in the carrier device from falling down from theremaining section of the device, a plural sets of four rollers aredisposed on four sides of the remaining section of the device exceptingthat the inside rollers are omitted in the range of each belt wheelwhereby the remaining device section has a cross sectional profilecompletely closed.

For long workpieces, two pairs of carrier devices of channelled ehdlessbelt type may juxtaposed in tensioned state in the respective verticalplanes to form an X-shaped arrangement by having two pairs of beltwheels engaging the same respectively and rotated in the oppositedirections. The carrier device may advantageously have both side wallseach comprising a plurality of outwardly flared plates alternatingsimilar plates. These outwardly flared plates overlap each other whenthe associated portion of the device is traveling along a rectilinearpath between the associated pair of belt wheels. A layer of abrasives isformed on the ascending upper rectilinear section of each device andtransferred from the upper end thereof onto the ascending upperrectilinear section of the other devices through a transfer chute.Workpieces can be successively passed through an ascending streamportion of the abrasive layer on the upper rectilinear section of eachdevice.

The invention as to its organiztaion and its mode of operation as wellas other objects and advantages thereof will become more readilyapparent from the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a fragmental plan view of a surface finishing apparatusconstructed in accordance with the principles of the invention withparts removed for purpose of illustration;

FIG. 2 is a fragmental side elevational view of the apparatusillustrated in FIG. 1 with parts removed for purpose of simplificationand with parts broken away for the purpose of illustrating a position ofa workpiece relative to a stream of loose abrasives;

'FIG. 3 is a sectional view taken along the line III-III of FIG. andillustrating a roller set for the apparatus;

FIG. 4 is a fragmental side elevational view of a modification of theinvention with parts removed for purpose of simplification and withparts broken away for the purpose of illustrating a position of aworkpiece;

FIG. 5 is a fragmental plan view of the apparatus illustrated in FIG. 4with parts removed for purpose of simplification;

FIG. 6 is a sectional view taken along the line VIVI of FIG. 4 andillustrating a roller set for the apparatus;

FIG. 7 is a view similar to FIG. 6 and illustrating a section takenalong the line VIIVII of FIG. 4;

FIG. 8 is a view similar to FIG. 6 and illustrating a section takenalong the line VIlI--VIII of FIG. 4;

FIG. 9 is a fragmental diagrammatic view in side elevation, of anothermodification of the invention with parts removed for purpose ofsimplification and with parts broken away for the purpose ofillustrating a position of a workpiece relative to a stream of looseabrasives;

FIG. 10 is a front view of the apparatus illustrated in FIG. 9;

FIG. 11 is a fragmental side elevationl view, in enlarged scale of anupper end portion of a carrier device illustrated in FIG. 9;

FIG. 12 is a fragmental sectional view taken along the XII--XII of FIG.11; and

FIG. 13 is a view similar to FIG. 12 but illustrating a modification.

Quite unlike the commonly accepted concept the invention is based uponthe concept that workpieces either push against a surface of arectilinear stream of loose abrasives moving at a predetermined speed inone direction or move through that stream at a predetermined speed inthe opposite direction while they are maintained immersed into thestream.

Referring now to FIGS. 1 to 3 inclusive, there is illustrated a surfacefinishing apparatus of vertical recirculation type constructed inaccordance with the principles of the invention. An arrangementillustrated is of a medium capability and comprises a pair of verticalbelt wheels 10 and 12 vertically disposed at any desired intervaldetermined for the particular application with one of the belt wheels,for example, the wheel 10 serving as a driving wheel. Between the beltwheels 10 and 12 there is spanned in tensioned state a carrier device ofchannelled endless belt type generally designated by the referencenumeral 14. The carrier device 14 is substantially of a U-shaped crosssection and composed of any suitable expandable, durable material.Suitable examples of such a material involve a wire net made of astainless wire or the like into an expandable structure with minute meshopenings and such a wire net having bonded on the internal surface asteel wire fabric coated with any suitable plastic.

{In order to support and guide the U-shaped carrier device 14 evenduring its movement the bottom of the U is supported and guide by aplurality of bearing rollers 16 substantially coextensive with the sameand disposed at substantially equal intervals throughout the length.Disposed on the outer side wall of the device 14 throughout its lengthis one external guide roller 18 coextensive with the leg of the U in avertical plane passing through the longitudinal axis of each bearingroller 16 while one internal guide roller 20 similar to the roller 18 isdisposed on the internal side wall and directly opposing to each roller18 except for the ranges of each belt wheel 10 or 12. One set of thesethree rollers 16, 18 and 20 is diagrammatically illustrated in FIG. 3.

Thus it will be appreciated that the carrier device 14 is positioned ina space confined by the rollers 16, 18 and 20.

Then a quantity of abrasives 22 is loosely and unifor'rnly loaded in theinterior of the carrier device 14 throughout its length and up to anysuitable level for example, up to approximately two thirds the depth ofthe device to form a layer of abrasive in a closed loop.

It will be appreciated that the abrasives may be of the dry or wet typeor in the form of a paste. If desired, they may contain any suitableliquid such as water, a surface active agent, a glossing material etc.The abrasives may be in the form of a powder or a granule or a cakehaving any suitable shape such as a spherical, a pyramidal, arhombohedral, an ellipsoidal or a cylindrical shape or the like. Theymay have a mean diameter ranging from 0.01 to the order of 50 mm.dependent upon the material, configuration and dimension of workpiecesto be finished.

Under these circumstances, the carrier device 14 can be rotated in ahorizontal plane by the driving belt wheel 10 driven from an electricmotor (not shown) through a suitable transmission mechanism (not shown).It is now assumed that the belt wheels 10 and 12 are rotated in thedirection of the arrows designated within the respective circles 10 and12 to drive the carrier device 14 in the counterclockwise direction asviewed in FIG. 1 or clockwise direction.

In operation the carrier device 14 effects horizontal movement so thatany cross section thereof travels rectilinearly in the direction of thearrow 24 (see FIG. 1) between the centers of both wheels 10 and 12 whileit is guided by the rollers 16, 18 and 20 and subsequentlysemicircularly in the direction of the arrow 24' around the wheel 10 byvirtue of the latter and rollers 18 and 20 followed by rectilinearmovement in the direction of the arrow 24" between the centers of bothwheels and the subsequent semicircular movement in the direction of thearrow 24" around the driving wheel 12. Therefore it will be appreciatedthat with the carrier device 14 moved, any point on or in the layer ofabrasives 22 loaded in the device effects horizontal movement includinga pair of rectilinear movement portions between the centers of bothwheels and 12 and a pair of semicircular movement portions around therespective wheels with each of the rectilinear portion merged at eachend into the adjacent semicircular portion. In other words, movement ofthe carrier device 14 causes a stream of abrasives effecting movement ofthe character just described.

The length of the rectilinear movement of the layer of abrasives 22 andaccordingly a distance between the centers of the two belt wheels 10 and12 designated by the reference character L or L may be selected to haveany magnitude dependent upon the size of workpieces to be finished andthe capability of the apparatus to treat the workpieces per each day. Ithas been found that the distance L or L may be varied from a magnitudeas low as less than 1 meter to a magnitude exceeding 10 meters. Also thelayer of abrasives 22 may have any desired width and any desiredthickness in accordance with the particular application.

With the carrier device 14 moved in the counterclockwise direction asviewed in FIG. 1 to establish the stream of abrasives as abovedescribed, any suitable holding and driving means can be utilized tointroduce a workpiece 26 for example from its position 26 illustrated inFIG. 1 into the carrier device 14 adjacent the righthand and lower endportion thereof as shown at the arrow 28 whereupon the workpiece may bepushed against the surface of the lower rectilinear stream portion ofthe abrasives adjacent the end of the rectilinear movement portion.Alternatively the workpiece may be put in the stream. The holding anddriving means are symbolically designated by a small circle within therectangle of the workpiece in FIG. 1. Then the holding and driving meansare operated to move the workpiece 26 in counterflow relationship on thesurface or in the interior of the stream. One position of the workpiecebeing finished is illustrated at its position 26' in FIGS. 1, 2'and 3.

When the workpiece 26 has reached substantially the beginning or thelefthand end of the lower rectilinear stream portion or when it hassubstantially traveled the distance L, it can be raised from the streamof abrasives and then brought into its position 26 shown in FIG. 1 asthe finished product.

Alternatively if the workpieces 26 is required to be further finishedthen the raised workpiece 26" may be moved along its semicircular path28 around the wheel 10 by the same holding and driving means without itcontacting the semicircular stream portion of the abrasives. Thereafter,when the workpieces reaches above the end of the upper rectilinearstream portion it will be pushed against or put into that stream portionwhile it is moved in the direction of the arrow 28" or in counterflowrelationship to be further finished through the use of the same holdingand driving means. At the beginning or the righthand end of saidmovement portion the finished workpieces will be similarly raised fromthe stream and then brought into its position 26" illustrated in FIG. 1as shown at the arrow 28". Thus the workpieces 26 has been completelysurface finished.

In either case it is to be understood that a series of workpieces can besuccessively introduced into the carrier device 14 at any suitableintervals of time to be finished with the rectilinear stream portion orportions of abrasives in the manner as above described.

Thus it will be appreciated that the present apparatus can surfacefinish workpieces on the basis of production line. If a singleproduction line is desired, the workpieces 26 will be successively fedfrom their position 26 to their position 26." in the manner as abovedescribed. Alternatively if workpieces is surface finished on the basis01 double production line, the rectilinear portion designated at thearrow 24 of the carrier device 14 may be used t surface finish theworkpieces 26 on the line 28 while at the same time the portion thereofdesignated at the arrow 24" may be used to surface finish workpieces 27on the separate line 28".

From the foregoing it will be apparent that the invention comprises theuse of the rectilinear stream portion of the abrasives along for purposeof surface finishing. Therefore the method and apparatus of theinvention may be called the bee-line flow finishing type.

In practicing the invention the relative speed between the workpiece andthe rectilinear stream portion of the abrasives is of the mostimportance. In order to performing consistently uniform surfacefinishing with a high efficiency and low costs, one must consider anextent to which the pressure of the loose abrasives in its flowing layercan be applied to the particular workpiece. It has been found that, forsatisfactory results, the layer of abrasives should have a speed rangingfrom 70 to 300 meters per minute. A speed between and meters per minuteis generally effective for surface finishing workpieces [made of iron,steels, stainless steels, non-ferrous metals, etc. For extremely stoutor tenacious materials or for the purpose of heavy grinding, it has beenespecially found that the speed of the layer of abrasives may range from300 to 500 meters per minute without any damage to workpieces.

It should be understood that the workpieces are required to be put infinishing engagement with the rectilinear stream portion of theabrasives for a period of time suflicient to be thoroughly surfacefinished with the abrasives in that stream portion. Therefore theworkpieces must relatively travel the length L or L or L+L' of therectilinear stream portion, as the case may be, for such a period oftime. It has been found that that period of time is preferably in theorder of from 10 seconds to 15 minutes for the speed of the abrasivestream as previously specified. Also it has been found that the relativespeed between the workpieces and the rectilinear stream portion of theabrasives preferably ranges from 70 to 500 meters per minutes.

Referring now to FIGS. 4 to 8 inclusive there is illustrated amodification of the invention wherein a stream of abrasives such aspreviously described is established in a vertical plane. An arrangementillustrated may be called the horizontal recirculation type and isespecially suitable for use on a table.

The arrangement comprises a pair of spaced belt wheels 40 and 42disposed in a common hoizontal plane and a carrier device of channelledendless belt type generally designated by the reference numeral 44 andspanned in tensioned state between both belt wheels. The carrier device44 is formed of any suitable flexible, tough material such as a flaxfilled urethane rubber or the like and has a quantity of abrasives 52such as the abrasives 22 as previously described.

When a drive (not shown) rotates one of the belt wheels for example thewheel 40 in the direction of the arrow designated Within a circle 40 orin the counterclockwise direction as viewed in FIG. 4, any cross sectionof the device 44 travels along a closed loop comprising a rectilinearportion, semicircular portion, another rectilinear portion and anothersemicircular portion consecutive to each other as shown at the arrows54, 54', 54" and 54" respectively as in the arrangement illustrated inFIGS. 1 to 3 inclusive. In this case, however, it is noted that theclosed loop lies in a vertical plane. Therefore it is essential that anyportion of the abrasives 52 within the carrier device 44 should beprevented from falling down from that portion of the device as travelingalong the semicircular portion 54' or 54" or the lower rectilinearportion 54".

To this end, the carrier device 44 made of a flexible,

tough material as above described has a pair of opposed side walls 46longitudinally undulating with valleys 48 of the undulation disposed atsubstantially equal intervals and inwardly foldable. Disposed along themajor part of the upper rectilinear section 54 of the closed loop are aplurality of sets of a bearing roller 60 and side guide rollers 62 and64 (see FIG. 6) at substantially equal intervals to define the 'U-shapedcross section of the carrier device as traveling along the upperrectilinear section 54. These rollers 60, 62 and 64 may be identical tothe rollers 16, 18 and 20 as previously described in conjunction withFIG. 3 except for the concave contour of the roller 60. The rollers 60of concave contour are effective for centering the carrier device 44. Ifdesired, bearing rollers such as the bearing rollers 16 may be used.

Both a transitional region from the upper rectilinear section 54 to theadjacent semicircular portion 54 or 54" of the closed loop and eachadjacent portion of the semicircular portion are provided with aplurality of sets of four rollers 60', 62, 64, and 66' as shown in FIG.7 disposed at substantially equal intervals. The bearing roller 60' isidentical to the bearing roller 60 and two opposed side guide rollers 62and 64' are shorter than the side guide rollers 62 and 64 and inclinedtoward each other with the rider roller 66 of concave contour disposedabove the side rollers. As the side guide rollers 62' and 64' are nearto the belt wheel 40 or 42 they are more inclined toward each other andcorrespondingly the rider rollers 66 may be progressively shorter. Theroller sets 6266' are in rolling engagement with the adjacent portionsof the carrier device 44 whereby they cooperate with each other torender the upper opening of the U progressively narrower in one of thetransitional ranges until the opening is completely closed with bothlegs of the U somewhat overlap each other as shown in FIG. 8. In theother transitional range they serve progressively to open the upperopening of the U until it is completely opened at the entrance of therectilinear device section.

In order to maintain the closed sectional profile of the carrier device44 on the remaining portion of the closed loop or in the course of thereturn path, a plurality of sets of four rollers 60", 62", 64" and 66"as shown in FIG. 8 are disposed at substantially equal intervals and inrolling engagement with the adjacent portions of the device except forthe semicircular portion thereof. The roller set 60"-66" aresubstantially similar to that shown in FIG. 7 excepting that the sideguide rollers 62" and 64" are substantially parallel to each other andthat the rollers 60 and 66" are the lower and upper rollers acting as apressing and a bearing roller respectively.

For the semicircular portion 54' or 54" the roller sets are identical tothe roller set 60"-64" except for the side rollers 64" being omitted andinstead replaced by the belt wheel 40 or 42.

With the arrangement of the roller sets as above described it will beappreciated that any cross section of the carrier device 44 ismaintained U-shaped on the major part of the upper rectilinear portion54, and as it approaches the belt wheel 42 its upper opening becomesprogressively narrower until the opening is completely closed.Thereafter the cross section of the carrier device 44 travels along thereturn path 54'54"54 while it maintained closed and as it moves away forthe belt wheel 40 it is progressively open until it assume the U- shapeat the beginning of the upper rectilinear portion 54.

When the belt wheel 40 is rotated in the counterclockwise direction asviewed in FIG. 4 any cross section of the carrier device 44 travels inthe direction of the arrow 54, 54', 54" and 54" in the manner as abovedescribed. Therefore, within the carried device 44 as traveling alongthe upper rectilinear portion 54 of the close loop, a rectilinear streamof the abrasive having the effective length of L formed in that portion54. This stream is utilized to surface finish workpieces in the samemanmer as previously described in conjunction with FIGS. 1 to 3inclusive. Thus workpieces 56 successively pass from their startposition 56 to a working line 68 along which they are surface finishedand then delivered to their finished portion 56'.

As an example, an apparatus such as illustrated in FIGS. 4 to 8 was usedto surface finish pin-shaped workpieces and screws. While the pointedends of the pinshaped workpieces or the heads of the screws weremaintained projecting from the surface of the rectilinear stream portionof the loose abrasives they were successively passed through that streamportions at a relative speed as above specified for a period of time asabove specified. During movement they were tilted at any desired angleto the direction of the stream and/ or they were rotating about theiraxes. In this way their particular portions could be successfullysurface finished.

Referring now to FIGS. 9 to 13 inclusive, there is illustrated anothermodification of the invention especially suitable for surface finishinglong large-sized workpieces. Two pairs of chain wheels 110, a, 112 and112a having the horizontal shafts (not shown) are suitably supported ona machine frame (not shown) such that a line passing through the centersof the wheels 110 and 112 of one wheel pair crosses a line passingthrough the centers of the wheels 110a and 112a of the other pair toform an X-shaped arrangement. A pair of carrier devices 114 and 114a ofchannelled endless belt type as will be hereinafter described aretightly spanned bet-ween the wheels 110 and 112 and between the wheels110a and 112a respectively with endless chains and endless beltsinterposed therebetween. Thus both carrier devices are juxtaposed in anX-shaped arrangement. Only the chains and belt for device 114 are shownby the reference numerals 116 and 118 respectively. The lower wheels 110and 110a are adapted to be driven in the opposite directions by a commonelectric motor through a suitable transmission mechanism to rotate bothcarrier devices 114 and 114a in the corresponding directions and in therespective vertical planes although the motor and transmission mechanismare not shown for purpose of simplification. If desired, the upperwheels 112 and 112a may be similarly driven by the same motor. With thearrangement illustrated, any cross section of each device 114 or 114atravels along a rectilinear path between the associated pair of wheelsas in the previous arrangement.

The carrier devices 114 and 114a are of the same construction andtherefore one of the devices will now be described. As best shown inFIGS. 11 and 12, the carrier device 114 has a bottom composed of theendless belt 118 rigidly secured to the endless chain pair 116 engagingthe chain wheels 110 and 112 and both side walls each composed of aplurality of outwardly flared plates 120 alternating the similar plate121 with the plates 120 and 121 being attached to the chain 116 or thebelt 118 as shown in FIG. 12. These plates 120 and 121 overlap eachother when the associated portion of the carrier device 114 is movingalong the rectilinear path. When the plates are passing 'around eachchain wheel they will decrease in the overlapped area but still form thecontinuous side wall free from any gap therebetween. Therefore aquantity of abrasives loaded in the carrier device 114 as will bedescribed later is prevented from falling down from the side wall of thedevice during its movement.

As best shown in FIG. 10, a transfer chute 122 or 122a extends fromadjacent the upper chain wheel 110 or 110a for one of the carrierdevices 114 or 114a to that portion of the other carrier devicepositioned directly below the top of the one carrier device to permitthe abrasives to transfer from one to the other of the carrier devices.

In order to initially load a quantity of abrasives into each of thecarrier devices 114 or 114a, both devices may be first driven in themanner as previously described. Then a quantity of abrasives is fed intoeach of the moving carrier devices 114 or 114a from the lower end of 1tsupper rectilinear section formed between the associated upper and lowerwheels or the associated chute 122 or 122a to form a layer 124 or 124aof abrasives loosely and uniformly distributed to a predetermined depthin the upper rectilinear carrier section throughout the length whereuponfeeding of the abrasives terminates. It is to be noted that each of thecarrier devices should be inclined at such an angle that the layer ofabrasives 124 or 124a does not collapse within the ascending rectilinearcarrier section. As soon as any portion of the abrasive layer 124 hasreached the upper end of the ascending rectilinear carrier 114 sectionit falls down onto the other rectilinear section through the associatedchute 122. Then the falling portion of the abrasives in the form of alayer ascends in the rectilinear section as the latter moves upwardly.When any portion of the abrasive layer 124a has reached the top of thelatter section, it falls down onto the original rectilinear carriersection through the chute 122a to repeat the process just described.Thus it is apparent that the layers of abrasives 124 and 124a travelalong a closed loop 1ncluding a pair of rectilinear portion inclined andcrossing each other. Namely there have been established a pair ofrectilinear stream of the abrasives crossing each other into an X-shapedarrangement.

Under these circumstances, holding and driving means of any knownconstruction can be used tosurface finish workpieces one after anotherwith either or both of the two rectilinear abrasive streams in thesimilar manner as previously described in conjunction with FIGS. 1 to 3inclusive. For example, one of workpieces 126 is fed in the direction ofthe arrow 128 from adjacent the upper end of the rectilinear carriersection into the carrier device 114 through the use of holding anddriving means schematically designated at a rod connected to theworkpiece 126. In the carrier device 114 it descends along therectilinear carrier section in counterfiow relationship while beingsurface finished with the abrasives in the rectilinear abrasive stream.Near its position just below the upper wheel 112 the workpiece is movedfrom the carrier device 114 to its position 126 as shown in thedott-and-dash arrow 128'. Thereafter the workpiece is moved in the othercarrier device 114a as shown at the dott-and-dash arrow 128" and 128"(see FIG. with its orientation remaining unchanged. Then the work piecesuch as 126 (iv) is subject to surface finishing in the carrier device114a in the same manner as in the device 114 after which the workpieceis passed from the device 114a to its position 126 In this way theworkpiece has been completely surface finished. The process justdescribed is repeated with the succeeding workpieces.

Alternately the surface finishing operation may be started with thecarrier device 114a with the workpieces transferred from the device 114ato the devices 114 at the lefthand side thereof as shown at thedott-and-dash arrow 128" (see FIG. 10).

In FIGS. 9 and 10 the stream of abrasives are designated at the arrows120, 120, 120 and 130, 130', 130" etc. and the workpieces being surfacefinished are illustrated at various positions 126', 126" etc.

From the foregoing it will be appreciated that according to the surfacefinishing operation as above described, the workpieces are surfacefinished in the opposite directions resulting in no occurrence ofpartial polishing and polishing shadows due to the conventionalunidirectionally surface finishing methods and hence in uniform andhomogeneous finishing. This is particularly effective for surfacefinishing long workpieces such as mufflers for use in autobicycles,bumpers, radiator grilles and decorative straps for use in automobilesand the like. It will be also understood that the workpieces within oneof carrier devices 114 or 114a are automatically maintained at an angleof inclination corresponding to that of the latter and that theworkpieces transferred from the device 114 to the device 114a and viseversa have an angle of inclination automatically varied so as tocorrespond that of the device 114a or 114 by the action of resistance tothe workpieces of the rectilinear abrasive stream.

Alternatively both carrier devices 114 and 114a may be put in separateworking lines beginning at the position 126 and 126 and terminating atthe position 126" and 126 If desired, the chutes 122 and 122a each maybe operatively coupled with a motor-operated vibrator (not shown) to aidin transferring the abrasives from one to the other of the carrierdevices. Althernatively, a rotary disk or rollers (not shown) may bedisposed on the bottom of each chute.

Dependent upon their configuration, the workpieces may effect, inaddition to rectilinear movement in the rectilinear abrasive stream,rotational movement about their axes and/or serpentine movement in thevertical and/ or horizontal directions or direction.

Conveniently cover means (not shown) may be provided for covering eachof the carrier devices 114 or 114a to prevent the abrasives fromscattering from the associated device.

With the wet type of abrasives used a liquid such as water containing asuitable compound or compounds may be poured into the layer of abrasives124 or 124a at the upper end of the associated rectilinear carriersection and exhausted from the lower end of each chute (not shown).

If desired, the endless chain pair may be omitted and instead of theendless belt may directly engage belt wheels used in place of the chainwheels as shown in FIG. 13 wherein like reference numerals designate thecomponents similar or corresponding to those illustrated in FIG. 12.

The figures of the speed and dimension of the rectilinear abrasivestream, the speed of the workpiece relative to the latter and thefinishing time referred to the arrangement shown in FIGS. 1 to 3inclusive are equally applicable to the arrangement illustrated in FIGS.4 to 8 or FIGS. 9 to 13 inclusive.

Unlike the conventional type of gyration finishing methods in which acylindrical barrel having loosely loaded therein a quantity of abrasivesis rotated to form a flowing layer of the abrasives in the form of adisk, a cone, or a cylinder, and wherein workpieces are forced on or putinto the flowing layer to be finished, the invention is characterized inthat a rectilinear stream of abrasives is used resulting in thepossibility of easily subjecting workpieces to uniform surface finishingfree from partial polishing and/or polishing shadows due to theconventional finishing methods.

While the invention has been illustrated and described in conjunction tothe several preferred embodiment thereof, it is to be undertood thatvarious changes and modifications may be resorted to without departingfrom the spirit and scope of the invention. For example, the arrangementshown in FIGS. 1 to 3 and FIGS. 4 to 8 inclusive may be rotated in theclockwise direction rather than counterclockwise direction with theworkpieces moved in a direction reversed from that described.

What I claim is:

1. A method of surface finishing workpieces, comprising the steps ofestablishing a stream of loose abrasives circulating at least partlyalong a rectilinear path while that portion of the abrasives movingalong said rectilinear path has a substantially uniform density and apredetermined cross sectional profile, and moving workpieces one afteranother relative to said rectilinear stream (beeline flow) portion ofabrasives at a predetermined relative speed in a direction opposite tothe direction of the stream while maintaining said workpieces insurface-finishing engagement with said beeline flow portion ofabrasives.

1 1 1 2 2. A method of surface finishing workpieces as claimed FOREIGNPATENTS in claim 1, wherein said predetermined relative speed 647 49612/1960 Great Britain. ranges from 70 to 500 meters per minute. 40175311/1933 Great Britain References Cited UNITED STATES PATENTS 2,448,3168/1948 Lesavoy 51--317 X US. Cl. X.R. 3,031,802 5/1962 Leliaert. 51-17,292

5 JAMES L. JONES, JR., Primary Examiner.

